FCOG-0945

You’re looking after a 24-year-old woman who is experiencing pelvic pain. She has one-sided pain that is widespread and mild, but can be intense at times. Menstruation has been regular. She denies having fever.

With the exception of a smooth movable adnexal mass on the right side, her pelvic examination seems normal.

Which of the following is the most likely reason for your discomfort?